Jack structure



. Sept. 26, 1944. E. sTRoM JACK STRUCTURE Filed NOV. v10,1941.

Patented Sept. 26, 1944 UNITED STATES PATENT OFFICE JACK STRUCTUREErnest Strom, St. Paul, Minn., assignor to Vulcan Manufacturing Co.,Inc., St. Paul, Minn., a corporation oi' Minnesota Application November10, 1941, Serial No. 418,462

.6 Claims.

My present invention relates to a Jack structure of the hydraulic bumpertype.

I One object of the invention is to provide a relatively light, yetpowerful jack of this general character which is comparativelyinexpensive to manufacture.

Another object is to provide a hydraulic jack structure having novelmeans for transferring oil from a reservoir to a lifting cylinder orfrom the cylinder back to the reservoir, such means including apartition member between the lifting cylinder and reservoir wherein apump structure is located.

Still another object is to provide the partition member assembled byscrewing of the reservoir into the lifting cylinder.

A further object is to provide an intake check valve 'in the partitionmember which is movable laterally and an outlet valve which is movablevertically, the pump plunger being coactible with both valves to movethem'to an unseated position to permit return of oil when desired,screwthreaded means being provided to effect a ne adjustment of thevalves for regulating the speed of return of the jack.

Still a further object is to provide a lifting hook on the jackstructure which may be vertically adjusted to any one of severaldifferent positions by a simple lifting movement of the hook and slidingthereof along the lifting. cylinder to a position where a lug of thehook may enter a y desired one of Va plurality of spaced openings formedin a channel shaped member arranged longitudinally of the liftingcylinder.

Still a further object is to provide afoot member for the jack structurewhich may be formed of heavy sheet metal and secured to the jack byavcotter key or the like in such manner that the foot plate may becanted to an angular position to conserve space when storing the jack onthe tool box or under a seat of the automobile.

With these and other objects inview; my invention consists in theconstruction; arrangement and combination of the various parts of mydevice whereby the objects contemplated are attained, as hereinaftermore fully set forth, pointed lout in my claims and illustrated in theaccompanying drawing. Although the invention is susceptible of a varietyof embodiments, it is unnecessary to fully describe and illustrate morethan one in order to give a full understanding of the invention bothfrom its structural and functional standpoints. Accordingly, I haveillustrated a preferred and desirable embodiment of the invention in theaccompanying drawing, in which:

Figure 1 is a perspective view of a jack struc ture embodying myinvention;

Figure 2 is an enlarged vertical sectional view with parts broken awayto conserve space on the drawing;

Figure 3 is a sectional view on the line 3--3 of Figure 2, and

Figure 4 is a sectional View similar to the cenv tral portion of Figure2, showing certain parts in a different position.

On the accompanying drawing, I have usedl the reference numeral I0 toindicate a foot plate. The plate lo may be Vpressed from heavy sheetmetal, with a socket at' I3 and a plurality of depressions I6 adapted tobite into the ground when using the jack. The plate I0 also has a pairof groovelikc extensions I5 in opposite directions from the socket I3.

A stationary plunger I2 in the form of a tube or rod has a rounded lowerend seated in the socket I3 and retained therein by a cotter pin I4. Theaxis of the pin I4 is crosswise relative to the grooves I5 so that whenthe jack is stored in the tool box or under the seat of the automobile,the foot plate may be tipped up to a position closely adjacent theplunger I2 to conserve space.

A lifting cylinder I'I surrounds the stationarll plunger I2 and isguided relative thereto by packing I8 and a guide ring I 9. The upperend of the lifting cylinder II has a partition member P seated thereinand retained in its seated position by a reservoir 20. The reservoir 20is threaded into the lifting cylinder II against va of the liftingcylinder. At the same time, packing 23 is compressed between thereservoir 20 and the upper end of the lifting cylinder` to eiectasealatilflifsptiii'li.v f ,1r

The partition member P has an intake valve seatmember- 24 screwedlaterally into it. An intake check valve 25 of ball type is adapted toseat thereagainst under the bias of a spring 2S. An outlet check valve21 is arranged to be normally seated against a. seat 28 of the partitionmember P by a spring 29. A cotter key 30 retains the spring 29 inposition and also a follower washer 3la for the gasket washer 22.

- A pump cylinder 3I is provided in the form of a tube threadedlymounted in the upper end of packing 35 therein effect an oiltight seal.The upper end ofthe pump plunger is threaded into a fitting 36 which inturn is connected with a` cap 31. An actuating sleeve 33 is secured tothe cap 31 as by a friction or press fit and a suitable weldedconnection after the parts are associated. A lock nut 3! is mounted onthe pump plunger 32 to retain it in the fitting 38.

The fitting 36 has a coarse threaded exterior adapted to coact withthreads in a boss 40 of the reservoir top 34. The reservoir has a nllerplug at 4i and the actuating sleeve 33 has a vent opening at 42, thepurpose of which will hereinafter be described. i

A lifting hook H is vertically adjustable with respect to the liftingcylinder i1. The hook H is formed on a loop member having a front part43, side parts 44 and a rear part 45. The front part 43 is located at'asubstantially lower elevation than the rearpart 45. The part 45 has alug or projection 46 adapted to selectively enter any one of a pluralityof openings 41 formed in a channel shaped member 43. The member 48 hasits flanges shaped to fit the lifting cylinder I1 and suitably securedthereto as by spot welding, indicated at 49.

Practical Operation In the operation of my jack structure, the hookmember H may be roughly adjusted to the desired elevation on the liftingcylinder I1 by tipping it upwardly as to the dotted position of Figure2, vertically adjusting it, and at the desired height permitting the lug46 to enter the opening 41 there found. The lifting hook may then beelevated by moving the cylinder i1 upwardly relative to the plunger i2,which is accomplished by actuating the pump plunger 32. On the upstroke,as shown in Figure 4, oil will be drawn in through the valve 25 from thereservoir 20 and into the pump cylinder 3|. On the down stroke, this oilcloses the valve 25 and opens the valve 21 as it is displaced from thepump cylinder 3l and the vertical bore in the partition member P. Thecheck valves will hold the load at any desired elevation.

When it is desirable to lower the Jael-:,the actuating sleeve 38 ispushed downwardly as far as it will go, which will result in the reducedend 33 of the plunger 32 almost touching the valve 25. The sleeve 38 isthen rotated clockwise to cause the threaded tting 33 to rotate in thehub 40. This operation causes a relatively slow movement downward of thepump plunger 32, with plenty of leverage for causing the reduced end 33to rst open the valve 25 by forcing it laterally and then finallyopening the valve 21 by forcing it downwardly. The degree of opening ofthe valve 21 will determine the speed of descent of the jack and thespeed can be nicely controlled by rotating the sleeve 33. When thethreads 36 are right hand, then clockwise rota; tion of the sleeve 38will lower the pump plunger 32 for the valve opening operation.

During the downward movement of the sleeve 38 as it is reciprocated, theair trapped therein may pass freely out through the vent 42. As thesleeve is moved upwardly, air passes freely in through the vent`42 so asto prevent any drag on the pumping operation. The illler plug 4i may beremoved and additional oil placed in the reservoir 20 when necessary.Leakage of the oil from the jack is effectively prevented, however, thelower packing I8 and the upper packing aandoen K Some changes may bemade in the construction and arrangement of the parts of my devicewithout departing from the real spirit and pur pose of my invention, andit is my intention to cover by my claims any modified forms lofstructure or use of mechanical equivalents which may be reasonablyincluded within their scope withi out sacrificing any of the advantagesthereof.

I claim as my invention:

1. In a Jack structure, a stationary plunger. a lifting cylindertelescopically mounted thereon, a reservoir screw threadedly mounted inand forming a continuation of said lifting cylinder, means fortransferring fluid from said reservoir to said lifting cylindercomprising a partition member having a flange engaged by said reservoiras it is screwed into said lifting cylinder and thereby retained inposition between the reservoir and lifting cylinder, a pump cylindercarried by said partition member, intake and outlet check valves in saidpartition member opening respectively from said reservoir and into saidlifting cylinder, a pump plunger reciprocable in said pumfp cylinder, anactuator therefor comprising a sleeve connected with said pump plunger,said pump plunger extending through the top of said reservoir, saidsleeve being telescopically mounted on said reservoir. said pump plungerbeing engageable with said intake valve to shift it of! its seatA andthen with said outlet valve to shift it on its seat to permit return ofoil through said outlet and intake valves from said lifting cylinderinto said reservoir, and means to cause such engagement of said pumrpplunger with said valves.

2. In a jack structure, a stationary plunger, a lifting cylindertelescopically mounted thereon, a reservoir screw threadedly mounted onsaid lifting cylinder, means for transferring fluid from said reservoirto said lifting cylinder comprising a partition member confined betweensaid reservoir and said lifting cylinder by their screw threadedconnection, a pump cylinder carried 4by said partition member, intakeand outlet check valves in said partition member opening respectivelyfrom said reservoir and into said lifting cylinder, said intake valveopening laterally and said outlet valve opening downwardly, a pumpplunger reciprocable in said pump cylinder, and an actuator thereforcomprising a sleeve connected with said pump plunger, said pump plungerextending throughA the top of said reservoir to said sleeve, said sleevebeing telescopically mounted on said reservoir, said pump rplunger beingengageable with said intake valve to shift it laterally oil' its seatand then, after passing said intake valve, beingl engageabie with saidoutlet valve to shift it downwardly oif its seat to permit return of oilthrough said outlet and intake valves.

3. In a jack structure, a stationary plunger, a lifting cylindertelescopically mounted on the upper end thereof, a reservoir separatefrom and mounted on said lifting cylinder, means for transferring fluidfrom said reservoir to said lifting cylinder comprising a partitionmember between said reservoir and said lifting cylinder, a pump cylindercarried by said partition member, intake and outlet check valves in saidpartition member opening respectively from said reservoir and into saidlifting cylinder, and a pump plunger reciprocable in said pump cylinderand extending through the top of said reservoir, said pump plunger beingengageable with Said intake valve to shift it on its seat and pass itand being then engageable with said outlet, valve to shift it off itsseat to permit return of oil through said outlet and intake valves fromsaid lifting cylinder into said reservoir, said plunger being smallerthan the passageway between said valves to permit such return.

4. In a jack structure, a plunger, a lifting cylinder telescopicallymounted thereon, a reservoir mounted on said lifting cylinder, means fortransferring fluid from said reservoir to said lifting cylindercomprising a partition member between said reservoir and said liftingcylinder, a Ipump cylinder carried by said partition member, intake andoutlet check valves in said partition member opening respectively fromsaid reservoir and into said lifting cylinder, said intake valve openinglaterally and said outlet valve opening downwardy, a pump plungerreciprocable in said pump cylinder, and an actuator therefore comprisinga sleeve connected with said pump plunger, said pump plunger extendingthrough the top of said reservoir to said sleeve, said plunger beingengageable with said intake valve to shift it laterally off its seat andthen with said outlet valve to shift it downwardly off its seat topermit return of oil through said outlet and intake valves.

5. A jack structure comprising a stationary plunger, a lifting cylindertelescoped thereon, a reservoir, pump and check valves to pump oil fromsaid reservoir into said lifting cylinder upwardly at the hook end tounlock said lug. relative to an opening of said channel shaped.

element to permit longitudinal adjustment of the lifting hook thereonand coaction of said lug with another selected opening.

6. In a jack structure, a plunger, a lifting cylinder telescopedthereon, a reservoir, pump and check valves to pump oil from saidreservoir into said lifting cylinder to displace said plunger therefrom,a lifting hook on said lifting cylinder comprising a loop portionencircling the lifting cylinder, a lug projecting inwardly from saidloop portion, a supporting hook on said loop portion opposite said lug,and an elongated channel shaped element longitudinally arranged on saidlifting cylinder with its flanges secured thereto and having spacedopenings in its web to selectively receive said lug.

ERNEST S'I'ROM.

